According to documentation
timers are only fired when the async executor is enabled (asyncExecutorActivate must be set to true in the flowable.cfg.xml, because the async executor is disabled by default).
What is the location of the flowable.cfg.xml file when Flowable is deployed in Tomcat? I am using Flowable 6.8. I copied the flowable rest and flowable ui apps in dropped them in webapps.